I would say that TMs are one of the most fundamental abstractions in CS - but as you note, for an abstraction they are actually quite concrete. I would perhaps argue that the lambda calculus is a slightly more fundamental abstraction - even of course they are equivalent in "power" to TMs.
I see where you're coming from with that, although personally I mostly think of them as different approaches of considering the same thing. A Turing machine asks the question of what a computer can be, while lambda calculus asks the question of what a computer program can be. You could also think of the TM as an abstraction of the imperative paradigm, and LC as as abstraction of the functional paradigm. We know they're theoretically equivalent, but they're different ways of conceptualizing it, and probably trying to figure out which is more basic is not a good use of our time :P
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I would say that TMs are one of the most fundamental abstractions in CS - but as you note, for an abstraction they are actually quite concrete. I would perhaps argue that the lambda calculus is a slightly more fundamental abstraction - even of course they are equivalent in "power" to TMs.
I see where you're coming from with that, although personally I mostly think of them as different approaches of considering the same thing. A Turing machine asks the question of what a computer can be, while lambda calculus asks the question of what a computer program can be. You could also think of the TM as an abstraction of the imperative paradigm, and LC as as abstraction of the functional paradigm. We know they're theoretically equivalent, but they're different ways of conceptualizing it, and probably trying to figure out which is more basic is not a good use of our time :P